diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 64ad1e034a..eb7e1f617d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -27,10 +27,10 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - name: set up JDK 11
+      - name: set up JDK
         uses: actions/setup-java@v5
         with:
-          java-version: '11'
+          java-version: 21
           distribution: 'temurin'
       
       - name: Cache Gradle wrapper dists
diff --git a/.github/workflows/docs.yml b/.github/workflows/docs.yml
index b3b32cc24d..a9a251923e 100644
--- a/.github/workflows/docs.yml
+++ b/.github/workflows/docs.yml
@@ -15,10 +15,10 @@ jobs:
     steps:
       - uses: actions/checkout@v6
 
-      - name: set up JDK 11
+      - name: set up JDK
         uses: actions/setup-java@v5
         with:
-          java-version: '11'
+          java-version: 21
           distribution: 'temurin'
 
       - name: Cache Gradle dependencies
diff --git a/extractor/build.gradle.kts b/extractor/build.gradle.kts
index 3e90d45d79..9e5098e2a4 100644
--- a/extractor/build.gradle.kts
+++ b/extractor/build.gradle.kts
@@ -40,6 +40,13 @@ tasks.test {
     dependsOn(tasks.checkstyleMain) // run checkstyle when testing
 }
 
+// https://checkstyle.org/#JRE_and_JDK
+tasks.withType<Checkstyle>().configureEach {
+    javaLauncher = javaToolchains.launcherFor {
+        languageVersion = JavaLanguageVersion.of(21)
+    }
+}
+
 checkstyle {
     configDirectory = rootProject.file("checkstyle")
     isIgnoreFailures = false
diff --git a/gradle.properties b/gradle.properties
new file mode 100644
index 0000000000..49765d3446
--- /dev/null
+++ b/gradle.properties
@@ -0,0 +1,7 @@
+#
+# SPDX-FileCopyrightText: 2025 NewPipe e.V. <https://newpipe-ev.de>
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+
+# https://docs.gradle.org/current/userguide/configuration_cache.html
+org.gradle.configuration-cache=true
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 8394b4a2fc..78687b9c3a 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -4,7 +4,7 @@
 #
 
 [versions]
-checkstyle = "10.26.1"
+checkstyle = "12.3.0"
 gson = "2.13.2"
 jsr305 = "3.0.2"
 junit = "5.14.1"
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index a4b76b9530..f8e1ee3125 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index e18bc253b8..8a848873f3 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.12.1-bin.zip
+distributionSha256Sum=72f44c9f8ebcb1af43838f45ee5c4aa9c5444898b3468ab3f4af7b6076c5bc3f
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.2.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
diff --git a/gradlew b/gradlew
index f3b75f3b0d..adff685a03 100755
--- a/gradlew
+++ b/gradlew
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 #
-# Copyright © 2015-2021 the original authors.
+# Copyright © 2015 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -114,7 +114,6 @@ case "$( uname )" in                #(
   NONSTOP* )        nonstop=true ;;
 esac
 
-CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
 
 # Determine the Java command to use to start the JVM.
@@ -172,7 +171,6 @@ fi
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
     APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
     JAVACMD=$( cygpath --unix "$JAVACMD" )
 
@@ -205,15 +203,14 @@ fi
 DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 # Collect all arguments for the java command:
-#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
 #     and any embedded shellness will be escaped.
 #   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
 #     treated as '${Hostname}' itself on the command line.
 
 set -- \
         "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
-        org.gradle.wrapper.GradleWrapperMain \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
         "$@"
 
 # Stop when "xargs" is not available.
diff --git a/gradlew.bat b/gradlew.bat
index 9b42019c79..e509b2dd8f 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -70,11 +70,10 @@ goto fail
 :execute
 @rem Setup the command line
 
-set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
 
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
 
 :end
 @rem End local scope for the variables with windows NT shell